Apparatus for recording and reproducing sound



Oct, 19,1943D c. M. CHORPENING 2,332,204

` APPARATUS FoR RECORDING AND REPRODUCING sUNp 2 sheets-sheet 1 Filed June 11,'1940 chien M. cuonv'emnerq Oct. 19, 1943. c.- M. cHoRPl-:NING '2,332,204

APPARATUS FOR RECORDING AND REFRODUCING SOUND Fned June 11, 1940 2 sheets-sheet 2 4 11: rl 11 1 1 1 'l rl l 3+ /s m jL 1; gvU-Wmwm'; 4; 3o //l lll//l/l/l//l/ Cuff M. CHRP'E'" In@ Patented Oct. 19, 1943 I OFFICE APPARATUS Fon aEcoaniNG AND aEPaoDUcmG soUND Creed M. Chorpening. Youngstown, Ohio, assignor to The Astatic Corporation, Youngstown, Ohio, a corporation of Ohio l Application June l1, 1940, Serial No. 339,861

12 claims. (ci. 17a-100.41)

This invention relates to apparatus for recording and reproducing sound and more particularly to a unitary device which is selectively operable to convert electrical impulses comingfrom a sound detecting device, as a microphone, into mechanical pulsations and to imprint such latter pulsations onto a permanent record, vsuch as a rotatable disk, or to detect the undulations of the record and convert the same into electrical impulses foroperating a sound emitting device, as a speaker for example. The invention seeks to simplify the design and construction of apparatus employed Afor sound recording and reproducing and has particular application to a combinational unit having the-two stated functions. Accordingly, the primary object of the invention is the provision of an apparatus for recording and reproducing sound which is simpler in design and more economical to construct than arrangements i heretofore devised for the combined purposes.

A further object of the invention is the provision of an apparatus for recording and reproducing sound which is operative toaccomplish its combined functions while requiring less manipulative eiort on the part of the user, whereby its range of usefulness is materially enhanced.

Another object of the invention is the provision of a translating unit which is operative to convert mechanical pulsations into electrical pulsations or vice versa, whereby the same unit may be employed either as a sound recording or a sound reproducing instrument but which nevertheless may be readily constructed at very low cost.

Amore specific object of the invention is the provision of an arrangement wherebya single translating element, as a piezo-electric crystal, may be utilized alternativelytorecord or reproduce sound. on' or from,l a conventional record, as

a rotating disk for example.

Yet another-object'of the invention is'the provision of a unitary translating cartridge which may be employed either for recording or reproducing, which may readily be operatively mounted on a stylus carrying arm of simple and economical construction, and which is at all times in Figure 1 is a plan view of :Im-*apparatus constructed in accordance with the principles ofthe invention;

Figure 2 is a side view of the apparatus of Figure 1,.some of the parts being shown in section;

Figure 3 isa sectional view of a detail of the Referring first to Figures 4i, 5 and 6 vof the i y drawings, the combined recording and translating unit of the invention is constructed in cartridge form and includes a casing having upper and lower sections I0 and Il, respectively, which .are provided with suitable registering apertures I2 to receive bolts or rivets, not shown, to hold the two' sections in rigid assembled relation. The casing sections I0 and II may be constructed in any known manner but are preferably molded of resinous plastic material or die cast from softmetaL A piezo-electric element I3, preferably a pair of superimposed Rochelle salt crystals hereinafter termed the crystal, is mcuntedwithin the casing being clamped at one 'endgthereof between the two clamping pads I4. The pads I4 are preferably of medium hard rubber and as Suchprovide a fairly rigid anchor for the ilxed end of the-crystal, Extending transversely across/one end of the casing sections I0 and II and partially received in grooves or recesses incorporated therein is the fibre strip I5 to which are attached a the terminal connectors I6. Conductors -I'I connect the terminal I6 with the respective crystal sections.

The mating-casing sections I0 and Il'are each provided with an inwardly directed boss I8 extending from a-corner of the end opposite the terminal end of the cartridge.l A semi-cylindri- In accordance with the usual practice the chuck 20 is provided with an inclined transverse bore vto receive the reproducing needle 5 or lstylus 23 and a threaded longitudinal bore to receive the needle clamping screw 24. The end of the chuck opposite the screw 24 is provided with a curved and bifurcated end 25. A metal clamp 26 is tted over the side edge of the crystal |3 adjacent the end opposite the fixed end of the crystal and is suitably insulated therefrom. Clamp 26 extends outwardly from the side of the crystal and its outer end is encased in a pad 21. The bifurcations of the end 25 of the chuck 20 t closely on either face of the clamp 26 with the pad 21 therebetween. Suitable damping pads 28 are provided between the chuck 20 and the casing.

Y A cylindrical bore 30 is provided in the end of the casing opposite the terminal end thereof with its axis substantially coincident with the principal axis of the crystal. A chuck 3| is journaled in the bore 30, a soft rubber bushing 32 being provided therein, and is provided with a vertically extending bore to receive the record cutting stylus 33. Chuck 3| is provided with a threaded bore to receive the stylus clamping screw 34. The inner end of the chuck 3| is bifurcated, as at 35, to fit over the end of the crystal |3. Damping pads 31'are positioned between the bifurcations 35 and the inner surfaces of the casing sections. It should be noted that the cutting stylus holder or4 chuck is closely coupled to the crystal element for the proper transmission of movement to the cutting stylus and that'the reproducing stylus lholder` is more loosely coupled to the crystal element to provide the proper low needle impedance for satisfactorily reproducing the record. The recording stylus holder is severely damped by the pads 31 and, if desired, limit screws or other adjustable device may be provided to limit the amplitude of oscillation of the recording stylus. It should be further understood that the above describedI recording and reproducing unit is at all times available for use either as a recording unit or a reproducing unit, depending on which holder and stylus are applied to the record.

It should be apparent that many changes may be made in the construction of the Aabove described recording and reproducing translator assembly, as for example the use of other specific' constructions for transmitting the vibrations from and tothe crystal, the use of crystals of other types than the torque type shown, and the use of separate crystals housed in the cartridge casing for recording and reproducing, but it should be understood that the latter modification would mitigate certain of the advantages attained by the use of the preferred illustrated embodiment of the invention. It is further specifically contemplated that instead of em- Playing the reproducing stylus chuck 20, which is substantially a rigid member, and providing the loose coupling by the pad 21 a yieldable torque wire maybe provided for the mechanical connection between the crystal and the stylus. The reproducing stylusmay be either of the replaceable .type or of a permanent type employing a Jeweled point.

In accordance with the preferred embodiment of the invention, theartridge housing the translating element4 and supporting the styluses is pivotally mounted in the outer end 40 of a pivotally mounted arm 4|. Arm 4|, which may be either a molded, cast or stamped article, is ordinarily provided with a top wall and side walls and an open bottom. End 40 is enlarged somewhat as shown to accommodate the cartridge and is provided in its outer end wall with a pair ofv vertically elongated apertures 42 to accommodate the stylus holding means 24 an'd 34. The side walls of the cartridge may be provided with conical indentations 43 adjacent the terminal end of the cartridge and conically tipped screws 44l are screw threaded through the side walls of the arm end 4l) with their inner ends received in the indentations 43, thus providing a pivotal supportfor the terminal end of the cartridge. The vertical length of the' apertures 42 allow limited pivotal movement of the cartridge about the pivot points 43. The center point and stylus end of the cartridge are, of course, biased to downward position by reason of the eccentrical disposition of the pivot points 43 and it ispossible, by so selecting the weight of the cartridge and the position of the points 43 longitudinally along the cartridge, to determine the downward force exerted on either of the styluses when the styluses support their end of the cartridge.

Arm 4| is carried by a revolvable post 46 which is journaled in a suitable bushing 41 carried by the top panel 48 of a record reproducing machine. Such machine will also include a turntable 50 for supporting a record disk 5| and in accordance with the usual practice the turntable is in turn supported and rotated by a vertical shaft 52.

In recording it is essential that the cutting stylus be moved across the face of the record at a constant rate and that the record be rotated at uniform speed. Shaft 52 is therefore. driven at constant speed by any suitable mechanism, not shown, and the arm 4| is coupled to the turntable for movement in synchronism therewith by the shaft 53 coupled with the shaft 52 by the worm reduction gears 54 and with the post 46 by means of the worm reduction gears 55 and a clutch 56. `The latter may include teeth 51 on one end of a worm wheel 58, which is normally freely rotatable on the post 46, and mating teeth y thereagainst.

on a collar 59, which is feathered on the shaft 46. Collar 58 is moved along the shaft 46 and into and out of engagement with. the teeth 51 by an arm 60 which extends up through the panel 48 and is provided at its outer end with a manually engageable knob 6|. It should be obvious that as-the knob 6| is moved to upper position the gear 58 will be coupled with the collar 59 and the post 46 rotated along with the turntable 50 but at greatly reduced speed.

Arm 4| is attached to the upper end of the post 46 by the flat head screw 63 which passes through an aperture in the upper wall of the arm and is screw-threaded into the post 46. A washer 64 of suitable friction material is interposed between the upper end surface of the post 46 and the arm 4| to provide in effect a friction clutch between the arm and the post. Any suitable expedient may be relied on to accomplish this function and in the apparatus specifically disclosed the shank of the screw 63 reaches the bottom of the bore in the post 46 and is screwed tightly The amount of friction provided is therefore determined by the thickness and character` of the washer 64.

In accordance with the preferred embodiment of the invention the bore in the cartridge casing to receive the reproducing stylus extends entirely through the casing and an alignedaperture 66 is provided in the upper wall ofthe arm end 40 to enable the stylus 23 to be moved to retracted position as shown in dotted lines in Figure 5.

During the normal'use of the apparatus of the invention both styluses will be retained in their respective holders with the reproducing stylus 23 extending downwardly below the cutting end of the stylus 33, as indicated in Figure 2 of the for supporting and rotating a record disk, an

arm mounted for pivotal movement about an axis parallel with the axis of rotation of said turntable and positioned outside of the marginal edge of the turntable,means to move said arm about said firstv mentioned axis in synchronism with the rotation of said turntable, means to render said rst mentioned means inoperative are screW-threadedly received in the sidewalls 1 lof the cartridge and extend out through vertically elongated apertures in the side Wall of the arm, may be provided. The screws 68 have cut and knurled outer surfaces and may conveniently be gripped between To condition the apparatus for recording and cutting purposes it is only necessary to retract the reproducing stylus 23 thereby allowing the lcutting stylus 33 to engage the face of the record and to elevate the knob 6| whereby the arm 5| will be geared to the turntable and be' moved across the face of the record as the record rotates. The friction disc 64venables theI arm 4| to be moved in opposition to the gearing to enable the cutting stylus to be accurately positioned adjacent the outer marginal edge of the record in beginning the record regardless of the oriented position of thegear 58.

It should be understood that the apparatus of this invention is equally operable for recording on pregrooved record blanks and this may be accomplished `by retracting the reproducing stylus as explained above and disengaging, the clutch E, in which case the arm 4| will be freely moved inwardly in accordance with the decreasingvdiameters of the convolutions of the groove. It should also be apparent that; if the apparatus is employed to play back a record which has previously been cut by the .same apparatus, the clutch 56 need not be disengaged as the driven travel of the reproducing stylus and the inward travel of the record groove is necessarily coincident.

An important advantage of the stylus arrangement of the preferred embodiment of the invention is lthat the cutting stylus may, if desired,

be permanently attached to its holder in properly oriented position by the manufacturer, thereby insuring the proper functioning of the apparatus.

I'he above specifically described embodiment the thumb and foreflnger "of the operator.

whereby said arm is freely rotatable, a support pivotally mounted on said arm adjacent the free end thereof for movement about an axis parallel with the plane of said record, said support being eccentrically mounted whereby the outer end thereof will be urged toward the plane of said record, a piezo-electric translating element carried by said support, a record cutting stylus closely coupled with said element and extending downwardly from the outer end of said support toward said record, a holder loosely coupled with said element and adapted to detachably receive a record reproducing stylus, and means to limit the pivotal movement of said support relative to said arm.

2. A combined sound recording and'reproducing unit comprising in combination a turntable for supporting and rotating a record disk, an arm mounted for pivotal movement about a. vertical axis positioned outside of the 'outer periphery of said turntable, means to move said arm about said axis and across the face of said turn-r table in synchronism with the rotation of said turntable, means to render said first mentioned means inoperative whereby said arm is freely rotatable, a support pivotally mounted on said arm adjacent the free end thereof for movement about a horizontal axis, said support being eccenof the invention should be considered as illustrative only as obviously many changes may be made therein without departing from the spirit or scope of the invention. It should be especially understood that the particular form of the arm and the method in which the same is geared to the record turntable is not per se any part of the invention'but is pertinent only insofar as itis.

combined with the novel recording and reproducing unit of the invention. This` unit comprising 'a cartridge may, of course, be used in conjunction with other forms of record blanks,

, such as cylinders, and in conjunction with anciltion.

What 1 claim is: Y 1. A combined sound recording and reproducing unit comprising in combination a turntable trically mounted whereby the outer end thereof will be urged toward the plane of said record, an electro-mechanical translating element carried by said support, a holder closely coupled with said element and adapted to receive a record cutting stylus, a second holder loosely coupled with said element and adapted to receive a record reproducing stylus, said last two mentioned means being carried by said support adjacent the outer end thereof.

3. A combined sound recording and reproducing unit comprising in combination a turntable for supporting and rotating a record disk, an arm mounted for pivotal movement about a vertical axis positioned outside of the periphery of said turntable, a support pivotally mounted on -said arm adjacent the free end thereof for movement about a horizontal axis, said supportbeing eccentrically mounted whereby the outer end thereof will be urged toward the plane of the record disk, a piezo-electric crystal carried by said support, a holder for a record cutting stylus carried by the outer end of said support and rigidly connected with said crystal, and a holder for a record reproducing stylus carried by the outer end `of said support and resiliently connected with said crystal. Y

4.- A combined sound recording and reproducing unit comprising in combination means to support and rotate a record blank, an arm adapted to move across the face of said blank, means to move said arm Ain accordance with the rotation of said record blank, a support pivotally mounted on said arm adjacent the free end thereof, said support being eccentrically mounted whereby the outer end thereof will be urged toward the face of the record, a piezo-electric translating element carriedL by said support, a

holder for a record cutting stylus carried by the outer end of said support and closely coupled with said element, and a holder for a record reproducing stylus carried by the outer end of said support and loosely coupled with said element.

5. Apparatus for recording and reproducing sound comprising in combination a supporting arm adapted to sweep across a record face, a support eccentrically pivoted on said arm, a translating element operative to convert electrical impulses into mechanical impulses and vice versa carried by said support,y a holder for4 a record cutting stylus carried by the normally unsupported end of said support and closely coupled with said element, and a holder for a record reproducing stylus carried by the same end of said support and loosely coupled with said element.

6. Apparatus for recording and reproducingsound comprising in combination a housing, a translating element operative to convert electrical impulses into mechanical impulses and vice versa in said housing, a holder for a record cutting stylus carried by said housing and closely coupled with said element, and a holder for a record reproducing stylus carried by said housing and loosely coupled with said element.

7. Apparatus according to claim 6 but in which said element is of the piezo-electric torque type, the axis of rotation of said first mentioned holder being substantially'coincident with the axis of twist of said element.

8. A combined sound recording and reproducing unit comprising a piezo-electric crystal of the torque responsive type, means to clamp said crystal along one of its ends, a member clamped.

to the other end of said crystal and being substantially coincident with the axis of twist of said crystal, a record cutting stylus operatively connected with said member, a second member clamped along a side edge of said crystal, a reproducing stylus, and means operatively connecting said reproducing stylus and said second member.

9. A combined sound recording and reproducing unit comprising in combination, a casing having mating upper and lower sections each provided with a pair of spaced parallel semi-cylindrical grooves extending throughout the thickness'oi one end wall and in the meeting base thereof whereby a pair of spaced parallel bores are provided when said sections are assembled, a piezo-electric crystal in said casing and clamped along one of its ends between said sections, said crystal being of the torque responsive type and having its axis of twist substantially coincident with the principal axis of one of said bores, a cutting stylus holder journaled in the said one of said bores and having a bifurcated end to clamp over the adjacent edge of said crystal, a reproducing stylus holder journaled in the other of said bores and provided with a curved and bifurcated inner end, a bifuracted member received over a side edge of said crystal and projecting within the bifurcations of the curved end of said holder, and a pad of cushioning material between said second mentioned bifurcations on the inner end of said 10. A combined sound recording and reproduclng apparatus comprising in combination a piezoelecrtic element operative to convert electrical impulses into mechanical impulses and vice versa, said element having a xed portion and movable portions, a record cutting stylus holder rigidly connected with a, movable portion of said element, and a record reproducing stylus holder resiliently connected with a movable portion of said element. v

l1. A combined sound recording and reproducing apparatus comprising in combination a translating element operative to convert electrical impulses into mechanical impulses and vice versa, said element having a xed portion and movably portions, a record cutting stylus holder rigidly connected with a movable portion of said element, and a record reproducing stylus holder resiliently connected with a movable portion of said element.

12. Apparatus according to claim 10 further characterized in that said element is of the torque type, the axis of rotation of said first mentioned holder being substantially coincident 

